Semiconductor Wafer Defect measurement technology

This picture demonstrates the significance of conducting pattern checks on wafers through multiple inspection points during the semiconductor manufacturing process. These inspection points can effectively monitor and control the output, ensuring the quality and performance of the final products.

Bright-field and dark-field wafer inspection technologies are complementary and are typically used to meet different application requirements. Ming field imaging (Brightfield imaging) collect the reflected light, bright field testing for light source and the wafer surface vertically. Light is reflected back from the surface, forming a "bright" image that truly shows the patterned features on the wafer, similar to how a mirror clearly and accurately reflects a person's face. Bright-field detection is mainly targeted at high-sensitivity applications, but its detection speed is low.

Dark field imaging (Darkfield imaging) dark field testing or oblique lighting you can use the normal lighting, light irradiation at a certain Angle to the surface of a wafer. The dark field mainly collects scattered light. When a beam of light encounters the inclined or rough surface features in the nanoscale pattern of a chip, its trajectory will change. Collecting these scattered lights can generate images of the edges of 3D structures in a dark background. Dark fields are suitable for low-sensitivity applications - typically for defects of 20nm or larger - and offer very high detection speeds.

Traditional dark field imaging (Traditional darkfield) light source with bevel radiation to the surface of a wafer, typically use a hood (as shown in figure of black cone) to stop the direct reflection. It has extremely high sensitivity to extremely small defects, but the detection speed may be relatively slow.